A team of scientists has discovered a giant tail of gas leaking from an exoplanet near Earth, which stretches up to 350,000 miles long – roughly 44 times longer than the diameter of our planet. The alien world, WASP-69 b, is a gas giant that orbits its star every 3.9 days and loses massive amounts of helium and hydrogen gas into space.
Researchers detected the tail using data from the W.M. Keck Observatory in Hawaii and found it to be much longer than initially thought. The tail forms when stellar wind blows the leaking gas away from the exoplanet, creating a trail in its wake.
“This tail is really valuable because it allows us to study the interactions between the planet’s atmosphere and the star’s stellar wind,” said Erik Petigura, co-author of the study. “By observing this extended tail, we can learn more about how gas giants form and evolve over time.”
The discovery provides scientists with a rare opportunity to measure the stellar winds of distant stars by using the tail as a giant “windsock.” The researchers analyzed the data from the W.M. Keck Observatory and found that the exoplanet’s helium tail extends at least seven times the radius of the planet itself.
WASP-69 b is a gas giant similar in size to Jupiter but less massive, and orbits its star roughly 160 light-years from Earth. The exoplanet has lost up to 200,000 tons of gas per second due to superheating by the star, which could have led to it losing up to seven Earth masses during its lifetime of around 7 billion years.
Source: https://www.livescience.com/space/exoplanets/nearby-exoplanet-has-grown-a-tail-44-times-longer-than-earth-and-its-acting-like-a-giant-stellar-windsock